Platelet-rich plasma (PRP) therapy for knee arthritis: a feasibility study in primary care

Potential therapeutic strategies for osteoarthritis via CRISPR/Cas9 mediated gene editing

Osteoarthritis (OA) is an incapacitating and one of the most common physically degenerative conditions with an assorted etiology and a highly complicated molecular mechanism that to date lacks an efficient treatment. The capacity to design biological networks and accurately modify existing genomic sites holds an apt potential for applications across medical and biotechnological sciences. One of these highly specific genomes editing technologies is the CRISPR/Cas9 mechanism, referred to as the clustered regularly interspaced short palindromic repeats, which is a defense mechanism constituted by CRISPR associated protein 9 (Cas9) directed by small non-coding RNAs (sncRNA) that bind to target DNA through Watson-Crick base pairing rules where subsequent repair of the target DNA is initiated. Up-to-date research has established the effectiveness of the CRISPR/Cas9 mechanism in targeting the genetic and epigenetic alterations in OA by suppressing or deleting gene expressions and eventually distributing distinctive anti-arthritic properties in both in vitro and in vivo osteoarthritic models. This review aims to epitomize the role of this high-throughput and multiplexed gene editing method as an analogous therapeutic strategy that could greatly facilitate the clinical development of OA-related treatments since it's reportedly an easy, minimally invasive technique, and a comparatively less painful method for osteoarthritic patients.

Protective Effect of Knee Postoperative Fluid on Oxidative-Induced Damage in Human Knee Articular Chondrocytes

The oxidative-stress-elicited deterioration of chondrocyte function is the initial stage of changes leading to the disruption of cartilage homeostasis. These changes entail a series of catabolic damages mediated by proinflammatory cytokines, MMPs, and aggrecanases, which increase ROS generation. Such uncontrolled ROS production, inadequately balanced by the cellular antioxidant capacity, eventually contributes to the development and progression of chondropathies. Several pieces of evidence show that different growth factors, single or combined, as well as anti-inflammatory cytokines and chemokines, can stimulate chondrogenesis and improve cartilage repair and regeneration. In this view, hypothesizing a potential growth-factor-associated action, we investigate the possible protective effect of post-operation knee fluid from patients undergoing prosthesis replacement surgery against ROS-induced damage on normal human knee articular chondrocytes (HKACs). To this end, HKACs were pre-treated with post-operation knee fluid and then exposed to H2O2 to mimic oxidative stress. Intracellular ROS levels were measured by using the molecular probe H2DCFDA; cytosolic and mitochondrial oxidative status were assessed by using HKACs infected with lentiviral particles harboring the redox-sensing green fluorescent protein (roGFP); and cell proliferation was determined by measuring the rate of DNA synthesis with BrdU incorporation. Moreover, superoxide dismutase (SOD), catalase, and glutathione levels from the cell lysates of treated cells were also measured. Postoperative peripheral blood sera from the same patients were used as controls. Our study shows that post-operation knee fluid can counteract H2O2-elicited oxidative stress by decreasing the intracellular ROS levels, preserving the cytosolic and mitochondrial redox status, maintaining the proliferation of oxidatively stressed HKACs, and upregulating chondrocyte antioxidant defense. Overall, our results support and propose an important effect of post-operation knee fluid substances in maintaining HKAC function by mediating cell antioxidative system upregulation and protecting cells from oxidative stress.

The use of platelet-rich plasma in studies with early knee osteoarthritis versus advanced stages of the disease: a systematic review and meta-analysis of 31 randomized clinical trials

INTRODUCTION

Reports have concluded that platelet-rich plasma (PRP) is an effective and safe biological approach to treating knee osteoarthritis (OA). However, the effectiveness of PRP in advanced stages of the disease is not entirely clear. The purpose of this study was to evaluate whether the use of PRP would be as effective in studies with early-moderate knee OA patients compared to studies including patients with end-stage OA, based on the Kellgren-Lawrence classification.

MATERIALS AND METHODS

A comprehensive search in MEDLINE, EMBASE, Scopus, and Web of Science databases was conducted to identify randomized controlled trials (RCTs) comparing the effect of PRP injections versus other intra-articular treatments on pain and functionality. A meta-analysis was conducted using a random-effects model and the generic inverse variance method.

RESULTS

We included 31 clinical trials that reported data of 2705 subjects. Meta-analysis revealed an overall significant improvement of both pain [MD, - 1.05 (95% CI - 1.41 to - 0.68); I² = 86%; P ≤ 0.00001] and function [SMD, - 1.00 (95% CI - 1.33, to - 0.66); I² = 94%; P ≤ 0.00001], favoring PRP. Subanalysis for pain and functional improvement showed a significant pain relief in studies with 1-3 and 1-4 Kellgren-Lawrence OA stages and a significant functional improvement in studies with 1-2, 1-3 and 1-4 knee OA stages, favoring PRP.

CONCLUSION

Our results indicate that including patients with advanced knee OA does not seem to affect the outcomes of clinical trials in which the effectiveness of the PRP in knee OA is assessed.

Injectable polymeric nanoparticle hydrogel system for long-term anti-inflammatory effect to treat osteoarthritis

Treatment of osteoarthritis (OA) by administration of corticosteroids is a commonly used method in clinics using anti-inflammatory medicine. Oral administration or intra-articular injection of corticosteroids can reduce the pain and progress of cartilage degeneration, but they are usually insufficient to show local and long-term anti-inflammatory effects because of their fast clearance in the body. In this study, we suggest an injectable anti-OA drug depot system for sustained drug release that provides long-term effective therapeutic advantages. Amphiphilic poly(organophosphazene), which has temperature-dependent nanoparticle forming and sol-gel transition behaviors when dissolved in aqueous solution, was synthesized for triamcinolone acetonide (TCA) delivery. Because hydrophobic parts of the polymer can interact with hydrophobic parts of the TCA, the TCA was encapsulated into the self-assembled polymeric nanoparticles. The TCA-encapsulated polymeric nanoparticles (TePNs) were well dispersed in an aqueous solution below room temperature so that they can be easily injected as a sol state into an intra-articular region. However, the TePNs solution transforms immediately to a viscose 3D hydrogel like a synovial fluid in the intra-articular region via the conducted body temperature. An in vitro TCA release study showed sustained TCA release for six weeks. One-time injection of the TePN hydrogel system in an early stage of OA-induced rat model showed a great inhibition effect against further OA progression. The OA-induced knees completely recovered as a healthy cartilage without any abnormal symptoms.

Safety and efficacy of a single intra-articular injection of a novel enhanced protein solution (JTA-004) compared to hylan G-F 20 in symptomatic knee osteoarthritis: a randomized, double-blind, controlled phase II/III study

Background

New minimally invasive treatments are vital to delay joint replacement surgery in patients with knee osteoarthritis. This study was designed to select the most effective among three formulations of an enhanced protein solution containing clonidine, hyaluronic acid, and human plasma (JTA-004), and compare the safety and efficacy of intra-articular administration of the selected formulation with a reference treatment (hyaluronic acid) in symptomatic knee osteoarthritis patients.

Methods

In this two-stage, double-blind, phase II/III study conducted in 12 Belgian centers, 50–79-year-old patients with primary knee osteoarthritis were randomized (1:1:1:1) to receive one dose of one of three JTA-004 formulations (differing in clonidine concentration [50 or 100 μg/ml] and volume [2 or 4 ml]) or the reference treatment (hylan G-F 20). Patients were evaluated using Western Ontario McMaster Universities (WOMAC®) Scores and the Short-Form health survey up to 6 months post-injection (Month 6). Drug consumption and safety were evaluated.

Results

Among 164 treated patients, 147 completed the study. The JTA-004 formulation containing 200 μg clonidine and 20 mg hyaluronic acid in 2 ml (JTA-200/2) was selected based on interim results at Month 6. The difference in adjusted mean change in WOMAC Pain Subscale Score from baseline (JTA-200/2 minus reference group) at Month 6 was − 9.49 mm; statistical superiority of JTA-200/2 over the reference was not demonstrated. No statistically significant differences in adjusted mean changes from baseline between JTA-200/2 and reference groups were observed for Pain, Physical Function and Stiffness Subscales WOMAC Scores, Total WOMAC Score, and Well-being Score at any timepoint, although JTA-200/2 induced larger improvements in WOMAC Scores than the reference. Statistically significantly larger improvements in WOMAC Pain Subscale Scores for JTA-004 versus the reference were observed in post-hoc analyses on pooled data from all JTA-004 formulations at Month 6 (p = 0.030) and Month 3 (p = 0.014). All JTA-004 formulations had clinically acceptable safety profiles.

Conclusions

This study provided preliminary evidence of the safety of intra-articular injection of JTA-004 in knee osteoarthritis patients. Phase III randomized controlled trials with larger sample sizes are needed to evaluate the efficacy of JTA-004 in knee osteoarthritis.

Trial registration

Clinicaltrials.gov/identifier NCT02740231;  clinicaltrialsregister.eu/identifier 2015–002117-30. Retrospectively registered 13/4/2016.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-021-04750-3.

Update on Novel Non-Operative Treatment for Osteoarthritis: Current Status and Future Trends

Osteoarthritis (OA) is a leading cause of pain and disability which results in a reduced quality of life. Due to the avascular nature of cartilage, damaged cartilage has a finite capacity for healing or regeneration. To date, conservative management, including physical measures and pharmacological therapy are still the principal choices offered for OA patients. Joint arthroplasties or total replacement surgeries are served as the ultimate therapeutic option to rehabilitate the joint function of patients who withstand severe OA. However, these approaches are mainly to relieve the symptoms of OA, instead of decelerating or reversing the progress of cartilage damage. Disease-modifying osteoarthritis drugs (DMOADs) aiming to modify key structures within the OA joints are in development. Tissue engineering is a promising strategy for repairing cartilage, in which cells, genes, and biomaterials are encompassed. Here, we review the current status of preclinical investigations and clinical translations of tissue engineering in the non-operative treatment of OA. Furthermore, this review provides our perspective on the challenges and future directions of tissue engineering in cartilage regeneration.

Platelet-rich plasma administering in osteoarthrosis treatment

Background — According to the data from the published sources worldwide, about 10% of the world population suffers from osteoarthrosis. While searching for novel methods of osteoarthrosis treatment, we proposed administering intra-articular injections of autologous platelet-rich plasma. The goal of this clinical study was to evaluate the effectiveness of autologous platelet-rich plasma injections in osteoarthrosis patient treatment. Methods — This open-label parallel-group study was a pilot randomized controlled trial. An analysis of the treatment outcomes for 128 patients with knee joint arthrosis was performed. All patients were split among three groups, and subjects in two of those were receiving conventional treatment. Clinical efficacy was calculated from pain intensity, determined using Visual Analog Scale, Lequesne index and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Inflammatory response intensity was assessed by superoxide dismutase content and erythrocyte catalase activity. Results — It was demonstrated that administering platelet-rich plasma allowed achieving tangible clinical and laboratory results without any side effects and with very few contraindications. The latter included, for instance, blocking inflammatory process in the joints, thereby inhibiting the oxidative stress, which is the most pathogenetically substantiated treatment of osteoarthrosis. Conclusion — Thus, we have discovered that platelet-rich plasma injections had apparent anti-inflammatory and pain-relieving effects, along with inhibiting action of destructive processes in the cartilaginous tissue, hence improving life quality of the patients with osteoarthrosis.

Platelet-rich plasma as an effective biological therapy in early-stage knee osteoarthritis: One year follow up

Objective: PRP is produced by centrifugation of whole blood containing highly concentrated platelets, associated growth factors, and other bioactive agents which has been shown to provide some symptomatic relief in early knee osteoarthritis (OA). The principal objective of our study was to evaluate the effectiveness and safety of standardized intra-articular injection of autologous PRP in early osteoarthritis knee. Methods: A total of 98 eligible symptomatic patients received two injections of standardized PRP 3 weeks apart. Clinical outcomes were evaluated using the VAS and Western Ontario and McMaster Universities Arthritis Index (WOMAC) questionnaire before treatment and at 6 weeks, 3 months, 6 months, and 1 year after treatment. Secondary objectives were safety (side effects), and the effect of PRP on the different grades of knee degeneration. Results: There was a statistically significant improvement in mean VAS and WOMAC scores at 6 weeks, 3 months, 6 months, and slight loss of improvement at 1 year follow-up. There was also a correlation between the degree of degeneration and improvement in the mean scores. The decrease in mean pain score is more in grades 1 and 2 (early OA) than in grade 3. The intraarticular injection is safe, with no major complications. Conclusion: PRP is a safe and effective biological regenerative therapy for early OA Knees. It provides a significant clinical improvement in patients with some loss of improvement with time. More studies will be needed to confirm our findings.

Efficacy and safety of intra-articular injection of mesenchymal stem cells in the treatment of knee osteoarthritis: A systematic review and meta-analysis

OBJECTIVE

To evaluate the effects and safety of intra-articular injection of mesenchymal stem cells on patients with knee osteoarthritis by a systematic review and meta-analysis.

METHODS

PubMed, EMBASE, and Cochrane Library were retrieved. An assessment of the risk of bias was done through the Cochrane Collaborative Bias Risk Tool, publication bias was assessed by plotting funnel plots and Egger tests. Pain and functional improvements in patients with knee osteoarthritis were determined by changes in VAS scores and WOMAC scores at baseline and follow-up endpoints. For the evaluation of MRI, the WORMS score and changes in cartilage volume were used. In addition, the number of adverse events in the intervention group and the control group were counted to explore the safety.

RESULTS

A total of 10 randomized controlled trials involving 335 patients were included. In the pooled analysis, compared with the control groups, the VAS scores of MSC groups decreased significantly (MD,-19.24; 95% CI: -26.31 to -12.18, P < .00001. All of the WOMAC scores also improved significantly: the total scores (SMD, - 0.66; 95% CI: - 1.09 to -0.23, P = .003), pain scores (SMD, - 0.46; 95% CI: - 0.75 to -0.17, P = .002), stiffness scores (SMD, -0.32; 95% CI: -0.64 to 0.00 P = 0.05), and functional scores (SMD, -0.36; 95% CI: -0.69 to -0.04, P = .03). Two studies with non-double-blind designs were the main source of heterogeneity. In terms of cartilage repair, there was no significant difference in the WORMS score, but there was a significant increase in cartilage volume in the MSC group (SMD, 0.69; 95% CI: 0.25 to 1.13, P = .002). The proportion of patients with adverse events in the MSCs treatment group was significantly higher than that in the control group (OR, 3.20; 95% CI: 1.50 to 6.83, P = .003).

CONCLUSIONS

Intra-articular injection of mesenchymal stem cells is effective and safety to relieve pain and improve motor function of patients with knee osteoarthritis in a short term which is different to conclusions of previous study.

Development of nanosilver doped carboxymethyl chitosan-polyamideamine alginate composite dressing for wound treatment

Nowadays, treatment to the infected wounds caused by bacterial even multi-resistant bacterial strains and subsequently complete skin regeneration remain a critical clinical challenge. Herein, a novel multi-functional platform (Alg/1.0Ag@CMC-PAMAM/PRP) was prepared as wound dressings by mixing platelet rich plasma (PRP) with the sodium alginate (Alg) based dressing containing nano silver (Ag)-doped carboxymethyl chitosan grafted polyamideamine (Ag@CMC-PAMAM) cationic polymers. The present dressings exhibited high swelling, suitable water vapor transmission rate (WVTR), and good mechanical properties and degradability, as well as sustained release of PRP. Besides, the component of Ag@CMC-PAMAM nanoparticles endow them with excellent antibacterial performance, while the incorporation of PRP promotes the effect of anti-inflammatory and angiogenesis by up-regulating relative activity factor expression of TGF-β1, CD31 and α-SMA and down-regulating the inflammatory-relative genes including TNF-α, IL-6 and IL-1β, all of which promote the closure of wound and produce a superior healing effect to the commercial Aquacel Ag group. This work indicates that the prepared Alg/1.0Ag@CMC-PAMAM/PRP wound dressing is a promising biomaterial with synergistic effect of antibacterial property and wound healing.

Effects of proximal fibular osteotomy on stress changes in mild knee osteoarthritis with varus deformity: a finite element analysis

BACKGROUND

Many previous studies lack sufficient quantitative evidences about changes in biomechanical properties of the knee in response to proximal fibular osteotomy (PFO). Therefore, the aim of this study was to compare the preoperative and postoperative effects of PFO on mechanical stresses in the knee joint and provide with a biomechanical basis for PFO in the treatment of mild knee osteoarthritis (KOA) with varus deformity.

METHODS

A total of 10 patients suffering mild KOA with varus deformity were enrolled in this study. Their image data from computerized tomography (CT) and magnetic resonance imaging (MRI) were used for finite element models, and PFO models were established. Static structural analysis was carried out using ABAQUS to compare the von Mises stress distribution and values of the maximal von Mises stress of femoral cartilage, meniscuses, tibial cartilages, and tibial plateau before and after surgery.

RESULTS

The stress distribution in the cortical bone of the tibial plateau showed that stresses were transferred from the anterior medial area to the posterior medial area after PFO. Values of the maximal von Mises stress in femoral cartilage, medial meniscus, medial tibial cartilage, and tibial plateau after surgery were significantly lower than the preoperative values, with statistically significant differences (P < 0.05). Postoperative values of the maximal von Mises stress of lateral meniscus and lateral tibial cartilage were significantly higher than the preoperative ones, with statistically significant differences (P < 0.05).

CONCLUSION

PFO could reduce the stresses in the medial compartment of the knee joint with stress pathways transferring from the anterior medial area to the posterior medial area of the tibial plateau. Therefore, PFO is recommended for the treatment of mild KOA with varus deformity featuring favorably pain-relieving effects.

The use of cellular matrix in symptomatic knee osteoarthritis

Knee osteoarthritis is a degenerative "wear and tear" disorder affecting mainly population over 50 years old. It can also present in younger people, especially after an injury or as a part of other diseases. While many therapeutic options exist for knee osteoarthritis, none of them has the potential to cure this condition. Cellular Matrix represents a combination of natural non-crosslinked hyaluronic acid (HA), thixotropic cell separation gel, and sodium citrate anticoagulant solution. A combination of Cellular Matrix with autologous platelet-rich plasma (A-PRP) is a novel therapeutic approach to the management of knee osteoarthritis. It is assumed that the active components HA and PRP have a synergistic effect contributing to a better therapeutic outcome in patients with knee osteoarthritis. Physiotherapy could provide an additional benefit. This is a retrospective pilot study assessing the potential benefit of Cellular Matrix and A-PRP combined with physiotherapy in the management of chronic knee osteoarthritis. Twenty-five patients were enrolled in the study and injected with three doses of Cellular Matrix combined with A-PRP with a time span of 2 weeks between each injection. All patients received standardized physiotherapy. The results showed that 68% of patients achieved more than 50% improvement in pain, stiffness, and function of the knee joints. There were no adverse reactions. This retrospective pilot study confirmed the positive effect of PRP and HA combination in the management of mild and moderate knee osteoarthritis. These preliminary results need to be verified in randomized control trials.

Platelet-inspired therapeutics: current status, limitations, clinical implications, and future potential

Recent research has been successful in demonstrating the importance of the addition of platelets to the field of cell-mediated therapeutics, by making use of different platelet forms to design modalities able to positively impact a wide range of diseases. A key obstacle hindering the success of conventional therapeutic interventions is their inability to produce targeted treatment, resulting in a number of systemic side effects and a longer duration for the onset of action to occur. An additional challenge facing current popular therapeutic interventions is biocompatibility of the system, resulting in the decline of patient compliance to treatment. In an attempt to address these challenges, the past few decades have been witness to the discovery and innovation of precision therapy, in order to achieve targeted treatment for an array of conditions, thereby superseding alternative mechanisms of treatment. Platelet-mediated therapeutics, as well as employing platelets as drug delivery vehicles, are key components in advancing precision therapy within research and in clinical settings. This novel approach is designed with the objective that the platelets retain their original structure and functions within the body, thereby mitigating biocompatibility challenges. In this article, we review the current significant impact that the addition of platelet-inspired systems has made on the field of therapeutics; explore certain limitations of each system, together with ideas on how to overcome them; and discuss the clinical implications and future potential of platelet-inspired therapeutics. Graphical abstract.

Extracorporeal shockwave therapy for the treatment of knee osteoarthritis: a meta-analysis

PURPOSE

Extracorporeal shockwave therapy (ESWT) has become a common practice for treating knee osteoarthritis (OA). However, the effectiveness and safety of this treatment are still questionable. This meta-analysis is aimed at determining the degree of pain reduction and functional outcome after ESWT for knee OA.

METHODS

We systematically searched MEDLINE, EMBASE, and other online databases. The articles comparing the outcomes between ESWT and controls were included in the analysis.

RESULTS

Nine studies with 705 patients were included. The pooled data revealed significantly lower pain scores in the ESWT groups than in the control groups within two weeks of treatment and six months after treatment (visual analogue scale, - 1.59, p = 0.0003, 95% confidence interval (CI) - 2.45 to - 0.72 at 2 weeks; - 1.12, p = 0.005, 95% CI - 1.89 to - 0.34 at 6 months). The ESWT group also had better functional outcomes four to six weeks post treatment (Western Ontario and McMaster Universities Osteoarthritis Index, - 11.96, p = 0.003, 95% CI - 19.76 to - 4.15). No rebound pain was noted for up to 12 months.

CONCLUSION

Using ESWT to treat knee OA may reduce pain and improve functional outcomes. The effect may last six months to one year. More prospective studies are needed to investigate the settings for ESWT to optimize treatment results.

The Current Status of Cell-Based Therapies for Primary Knee Osteoarthritis

There is a growing interest in cell therapy for knee osteoarthritis. This study systematically reviews the current status of cell-based therapies. The authors review treatment modalities, clinical outcomes, and the economics of cell therapy. Inclusion criteria were articles containing cellular therapy, platelet-rich plasma, and knee osteoarthritis in the title. Letters, editorial material, abstracts not published, and manuscripts with incomplete data were excluded. Forty-two articles met these inclusion criteria and were critically reviewed. Cell-based therapy holds promise as a means of restoring deficient local cartilage cell populations. There is no evidence-based information for the use of cell-based therapies in knee osteoarthritis.

Single- and double-dose of platelet-rich plasma versus hyaluronic acid for treatment of knee osteoarthritis: A randomized controlled trial

BACKGROUND

Platelet-rich plasma (PRP) and hyaluronic acid have been shown to be useful in the treatment of knee osteoarthritis. However, investigations comparing the efficacy of these two drugs together are insufficient.

AIM

To compare the outcomes of PRP vs hyaluronic acid injections in three groups of patients with bilateral knee osteoarthritis.

METHODS

This randomized controlled trial study involved 95 patients. Thirty-one subjects received a single injection of PRP (group PRP-1), 33 subjects received two injections of PRP at an interval of 3 wk (group PRP-2) and 31 subjects received three injections of hyaluronic acid at 1-wk intervals (group hyaluronic acid). The patients were investigated prospectively at the enrollment and at 4-, 8- and 12-wk follow-up with the Western Ontario and McMaster Universities Arthritis Index (WOMAC) and Visual Analogue Scale questionnaires.

RESULTS

Percentages of patients experiencing at least a 30% decrease in the total score for the WOMAC pain subscale from baseline to wk 12 of the intervention were 86%, 100% and 0% in the groups PRP-1, PRP-2 and hyaluronic acid, respectively (P < 0.001). The mean total WOMAC scores for groups PRP-1, PRP-2 and hyaluronic acid at baseline were 63.71, 61.57 and 63.11, respectively. The WOMAC scores were significantly improved at final follow-up to 42.5, 35.32 and 57.26, respectively. The highest efficacy of PRP was observed in both groups at wk 4 with about 50% decrease in the symptoms compared with about 25% decrease for hyaluronic acid. Group PRP-2 had higher efficacy than group PRP-1. No major adverse effects were found during the study.

CONCLUSION

PRP is a safe and efficient therapeutic option for treatment of knee osteoarthritis. It was demonstrated to be significantly better than hyaluronic acid. We also found that the efficacy of PRP increases after multiple injections.

Biologic Therapies for the Treatment of Knee Osteoarthritis

BACKGROUND

The use of biologic therapies for the management of knee osteoarthritis has increased, despite insufficient evidence of efficacy. Our aim was to complete a systematic review and analysis of reports utilizing the highest level-of-evidence evaluating: (1) platelet-rich plasma injections (PRPs); (2) bone marrow-derived mesenchymal stem cells (BMSCs); (3) adipose-derived mesenchymal stem cells (ADSCs); and (4) amnion-derived mesenchymal stem cells (AMSCs).

METHODS

PubMed, Embase, and Cochrane Library databases were queried for studies evaluating PRP injections, BMSCs, ADSCs, and AMSCs in patients with knee osteoarthritis. Of 1009 studies identified within the last 5 years, 123 met inclusion criteria. A comprehensive analysis of all levels-of-evidence was performed, as well as separate analysis on level-of-evidence I studies. Level-of-evidence was determined by the American Academy of Orthopedic Surgeons classification system.

RESULTS

Although the majority of PRP reports demonstrated improvements in pain and/or function, others revealed no substantial improvements. Similar findings were noted for BMSCs, ADSCs, and AMSCs. Assessments of BMSC studies yielded majority with positive clinical results, although short-lived. Studies on ADSCs revealed improved clinical outcomes, but equivocal radiographic outcomes. Studies evaluating AMSCs demonstrated improvements in pain and function, and decreased radiographic evidence of osteoarthritis.

CONCLUSION

Despite some promising early results for PRP, BMSC, ADSC, and AMSC therapies, the majority of level-of-evidence I studies have multiple problems: small sample sizes, potentially inappropriate control cohorts, short-term follow-up, and so on. Despite the limitations, there still appears to be evidence justifying their use for knee osteoarthritis management. More high-level, larger human studies utilizing standardized protocols are needed.

Triamcinolone Acetonide Extended-Release: A Review in Osteoarthritis Pain of the Knee

Triamcinolone acetonide extended-release (ER) 32 mg (Zilretta®) is approved in the USA for the management of osteoarthritis (OA) pain of the knee and is administered as a single, 5 mL intra-articular (IA) injection. Although the therapeutic effects from IA corticosteroids are typically short-lived, triamcinolone acetonide ER is formulated in poly (lactic-co-glycolic acid) (PLGA) microspheres that slowly release triamcinolone acetonide in the synovium, enabling their prolonged presence in the joint. This reduces systemic exposure and lessens corticosteroid-related systemic adverse reactions, such as blood glucose elevations. In a 24-week, randomized, phase III clinical trial, triamcinolone acetonide ER 32 mg significantly improved mean average daily pain intensity in patients with knee OA relative to placebo, and pain, stiffness and physical function (according to WOMAC criteria) relative to placebo and triamcinolone acetonide crystalline suspension (CS). Triamcinolone acetonide ER was generally well tolerated, with a tolerability profile similar to that of triamcinolone acetonide CS and placebo. Findings from a single-arm phase IIIb study indicated that a repeat administration of triamcinolone acetonide ER may be similarly efficacious to an initial injection without having deleterious effects on cartilage or other aspects of joint structure. Thus, triamcinolone acetonide ER expands the treatment options available for the management of OA pain of the knee.